Hi nipper, questions from a newbie here; anyone have suggestions where one would plumb in a vacuum gauge on an ej20 twin-turbo? Some early subarus(ea81?) apparently had unused ports on the intake manifold where you could 'plug-n-go' with your vacuum line, but I'm guessing I might have to tee into another line?

 

Is it really worth doing this? That is to say, is there an optimal rev range this will highlight to me, or should I just stick to the common sense approach, and use higher gears, go slower, etc.

 

manifold sounds like the pperfect spot. There you would see both vaccume and pressure.

 

nipper

 

The issue of reseting ECU before testing is a nonissue as ECU relearns fuel trims within minutes.

 

I know this can be true for lower octane as the knock sensor does its thing, but what about higher octane?

 

Carl

The hydrogen idea dosn't make sense conceptually, but supposedly works by faster combustion of the hydrogen effectively advancing the timing.

 

I discovered this great site that reviews the various "fuel saving" gadgets. There is also a case study on acetone. I think this guy hits a nail:

http://www.fuelsaving.info/debunk.htm

 

thanx for this - good link.

 

Carl

90% highway and 10% city, yup now i get -/+ 29mpg at 65-70 mpg, like i said i'm at 220 miles at half of tank. amazing. well my wallet is loving it.

In the light of the new facts I learned about acetone (see the other thread on acetone), your findings totally make sense. You used to get 23 mpg with 90% hwy driving at 65-70. This was way poor mpg for that speed. I get 26 mpg with 75 mph driving (AC off) in my 2000 legacy. My guess is that your engine runs very rich and your o2 sensor or some other emission sensor is way off. Now, the acetone leans out the mixture via chemistry on the o2 sensor and you are beck to where you are supposed to be.

According to my quick search, the acetone trick works only on older subarus, pre 99, that had different o2 sensors and possibly were fuealed too rich.

I get 27 with ac on, 28 in the tires, loaded with junk, driving 80+ and you can too. All you need is a hammer and beer.

 

 

 

 

Lots and lots of dents will create a turbulent mojo around your ride that allows you to ignore the laws of physics. That's about as technical as I dare get otherwise I'd prolly blow you away with my cunning use of addition AND subtraction to derive a precise explanation.

 

 

Or it could be the altitude I drive at.

d.

Like a golf ball ?

That must have been quite a hail storm !

What he forgot to mention is that the increase in mileage only happens when the vehicle is spinning!

What he forgot to mention is that the increase in mileage only happens when the vehicle is spinning!

You gotto be careful when you drive with all those hail dents. Sure you may get some "lift" and improve you overall gas mileage. But you risk the dreaded "slice" causing you to vere off-road burning all kinds of gas tearing through the back country.

But you risk the dreaded "slice" causing you to vere off-road burning all kinds of gas tearing through the back country.

That's the fun part.

d.

I get 27 with ac on, 28 in the tires, loaded with junk, driving 80+ and you can too. All you need is a hammer and beer.

Beer, huh? So it's alcohol, not acetone, that does it?

 

At least now I get the "Forester Titleist" reference.

my best, only city driving lots of short trips and including warm ups is about 12l/100km it's the same as 19mpg.

Do you think I could improve my mileage?

Hey guys,

I don't have a newer Suby anymore, just my '86 hatch. But I think it really comes down to basic stuff to save gas. Driving style, tire pressure, speed and general vehicle maintenance (e.g., air filters...) My hatch was getting a steady 26mpg on the hiway. Just changing my tire pressure from 35 to 41 psi, which for me has not changed the way the tires are wearing, has pushed my hatch to 30.5 to 32mpg regularly. This is at 65 to 70mph and it has a 4 speed. This has been for the last 4 months of driving back and forth to work. Granted this is all hiway driving about 65 miles each way. But this is from a carb'ed ea81 engine and the car is 4x4. When my wife drives our Hyundai, she gets between 42 and 44 mpg. I get about 37 - 39 mpg out of it, so I know it's all driving style (it has a little more oomph then the hatch ) Does adding chemicals to the gas help? I don't know, but I personally am a little doubtful. But let me know if anyone finds that it does help.

NV